DE1950508A1 - Pneumatic powered percussion hammer - Google Patents

Description

FMA Pokorny · jacftcne ² * ^{ok: tot) he} 19 ^ 9 Frankfurter Maschinenbau A (J 950508 FMA 2 - Dp / Schi 6 Frankfurt (Main) -West 13
Solmsstrasse 2/26

Druokluftibe-fcriebener

The invention relates to a pressure medium-operated, preferably air-powered percussion hammer, the consisting of cylinder, percussion piston, drill head and hollow cylinder connection piece for the drill pipe.

The shaft of the percussion piston is in a cylinder-proof guide bush arranged. .

On the cylinder side facing the tool in the central area of the connection piece is a compressed air control in the form a control valve is provided, the pressure medium can be controlled alternately in a conductive manner on different sides of the percussion piston is.

In the case of downhole hammers of this type, under certain circumstances occurring several times in the course of the drilling progress Operating condition of one or more blank strokes of the percussion piston, z. B. when immersing the drilling tool in a cavity in the rock or when withdrawing or lifting the Drill rods to prevent the tool from seizing up, measures and means within and on the compressed air control provided, by which an immediate interruption of the reciprocating movement of the percussion piston is brought about, wherein however, pressurized air is still blown into the borehole, which is used to discharge the cuttings.

The known solutions provide that in the event of a blank strike of the percussion piston from the compressed air control additional volume of air can flow into the upper cylinder chamber and the pressure medium pressure thus generated becomes the Impact piston prevented from further movements.

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A first known solution (DAS 1.256 597.8-24) see to it For this purpose, a shock absorber piston connected to the connecting piece is movably connected to a piston valve at the free end carries, which together with a valve seat in the cylinder of the percussion piston forms a Nebaneohlußventil .. The bore of the bypass valve opens into a chamber, preferably the head-side chamber, of the percussion piston cylinder.

V / uring the normal operation of the downhole hammer closes the piston valve the bore of the bypass valve to the head-side chamber of the percussion piston cylinder.

In the case of the abnormal condition (blank stroke), the piston valve releases the previously blocked bore / and through this bore An additional volume of air now flows over "the compressed air control into the percussion piston cylinder.

As a result of this additional volume of air, the percussion piston driven into an end position and hits the cylinder space delimitation. In the known case, this limit is formed the end face of the guide bush for the percussion piston shaft. The percussion piston remains in this end position, until normal operation has been initiated again. A single * stroke of the percussion piston edge at the transition between the two Piston head and piston skirt on the liner face each time a blank blow is not an alarming cause, to exit this bypass valve closure control method. It However, in the course of a drilling progress or further drilling progress multiple identical blank spaces will occur and with every blank impact the percussion piston hits the guide bush pin surface, before the piston movement is then immediately interrupted. '

- ο

This multiple impact destroys the guide bush face over time, and it will damage other hammer components until it is taken out of service and components need to be replaced.

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Another known solution (DAS 1.186.8l6) looks for the the same purpose that with the valve base, plate slide, Valve cover and valve pin existing control valve the valve cover has a through longitudinal bore, which is provided with laterally closable inlet channels and which also through a coaxial bore of the plate valve is connected to the upper cylinder space for the percussion piston.

In the plate slide bore, a spring-loaded valve pin is arranged displaceably guided, the other hand from the axially displaceable formed and arranged connecting piece of the drill string is loaded.

Seals during normal operation of the downhole hammer the valve pin closes the side inlet channels in the valve cover and prevents additional air from passing through the axial Plate slide bore can get into the upper cylinder space. ■

In the event of abnormal operating conditions (blank stroke), the valve pin releases the axial hole in the plate slide is free and an additional volume of air now flows through this hole the compressed air control in the percussion piston cylinder. As a result of this additional volume of air, the percussion piston is in the lower end position is driven and strikes the face of the guide bush for the percussion piston shaft. This solution therefore has the same unfavorable properties as the one described above. The disadvantage of known solutions is that when the measure of the additionally supplied compressed air, a required air cushion under the percussion piston is not sufficient to intercept it so that it does not strike the existing guide means.

As a result of repeated impacts of the percussion piston, not only the means of the piston guide are damaged, it can lead to the piston head and / or the cylinder jacket tearing. Even the hard shocks as a result of the impact piston hitting the intermediate guide can cause damage to the carbide tipping of the drilling tool.

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The purpose of the invention is to remedy these shortcomings. target . The invention is to provide a compressed air control by bes.timrr.i-e Training and arrangement of control components to sch which certainly prevent blank strokes of the percussion piston.

According to the invention, this is achieved by depending on the relative axial movement between the percussion hammer and connector in the extended end position of this two hammer components created throttle gap at the compressed air outlet end of the connector. The throttle gap is formed by an inner constriction of a compressed air flow Chamber within the Aneohlußstückes and a control head of a projecting into this chamber is arranged Control pin of the compressed air control. The chamber and control head are preferably designed and arranged in such a way that that the control head is in the inserted end position of the connector in the cylinder or in its Closure cap is located in the middle of the aforementioned chamber.

The choke effect can also be due to: a different Design and arrangement measure are effected, because the throttle gap, also known through an external constriction of the free end of the connecting piece and the inner wall of the hammer body leading to the connecting piece. the Inner wall is terner for the purpose of unthrottled air passage for normal operation in the direction of the control behind the Drosiel gap expanded in the shape of a truncated cone educated.

In one case, the one acts at the free end of the connection piece gebil'dete chamber together with the control head of a control pin belonging to the compressed air control, which axially into the Chamber through which compressed air flows into it. The control head is dimensioned in cross-section so that it is arranged in the extended end position in the middle of the chamber constriction (chamber constriction ·) is and leaves such a small gap free that

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causes the initiated through the hollow connector Compressed air volume in this area is throttled. These Throttling is sufficient to move the percussion piston into a Mch & " and to keep swinging · (prancing) movement. The percussion piston is due to the under and over the impact head Air cushions whose air volumes are still over the controls get there, never hit an end limit. . The same effect in terms of air throttling can also be achieved by removing the constriction on the outer circumference of the free end of the connector is provided, which together acts with the inner wall of the cylinder or the cap, in which the connecting piece is guided so as to be axially movable. The proposed throttle dimensions wire, in the event of an axial movement the hammer, which could cause a blank blow, the relative movement of the hammer contained in the control part and the connector used to immediately enter this axial movement to throttle the air flow flowing to the control. The cross sections of the throttle gap are so dimensioned - that sufficient compressed air volumes via the control still to the upper and lower percussion piston cylinder chamber can flow, which keep the percussion piston in slightly swinging movements and which, in addition, to the Blowing out the cuttings is sufficient.

For the time of the abnormal operating condition ο the work Hammer continues with reduced performance in the work rhythm, the percussion piston strikes because of what is present above and below sufficient air cushion no longer on the intermediate guide, so that damage is excluded.

Exemplary embodiments of the invention are shown and explained in the drawing.
It shows

Fig. 1 shows a hammer drill in longitudinal section (normal operating position) with control pin and connecting piece hollow chamber,

SAD ORIGINAL

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MA 2 - Thu / Ski - 6 - 2.10.69

Pig. 2 a percussion hammer in longitudinal section according to Pig. I (throttled operating position),

Pig. 3 is a detail of a modified percussion hammer in longitudinal section (normal operating position) with externally constricted connection piece, .

Figure 4 is a detail of a percussion hammer

according to FIG. 3 in longitudinal section (throttled "Operating position).

The percussion drill consists essentially of a cylindrical body 1, in the closure cap 2 a Connection piece 3 for the drill pipe partially shown Is slidably arranged, the compressed air control 5 with the adjoining cylinder 6, percussion piston 7 and drill bit 8 with tool 9.

The drill bit 8 is axially movable, but torsionally rigid in a hammer base 10 screwed to the body 1 arranged. The Sehlagkolbschaft 11 is in a ) Intermediate guide in the form of a guide bushing fixed in the body 1 12 arranged axially movable.

The compressed air control 5 consists of a lower part 13 and an upper part 20. The lower part 15 has, for. B. radially arranged air branching channels 14, which are connected to a common annular space 15, and a central axial bore l6 in which the control valve member 17 is axially movably guided, the plate of which is located in the annular space 18.

The air supply channels close to the control channels 14 Ϊ9 to cylinder 6.

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The upper control part 20 has the valve seat 21 and the air "passage channels 22. The lower and upper control parts together form an air distribution annulus 2J>.

The connection piece is designed as a type of hollow driver shaft , which is axially movable, but is arranged in the cylinder lock 2 in a rotationally rigid manner. That led out to the outside The end of Yes is screwed to the rod connector 4. The compressed air is fed to the controller 5 through the connector. -

The exhaust holes in the cylinder 6 are denoted by 24 and the air ducts leading to the drill bit are denoted by 25.

According to FIGS. 1 and 2, the upper part 20 is the compressed air control provided with a preferably centrally arranged control pin 26, the head 27 of which protrudes into the hollow connecting piece 3. ...-. ·. '..

The free, unrestrained end of the connector 2 is formed on the inside as a widened chamber 28 which is constricted by an inner collar 29 which preferably projects radially inward is trained. In the one pushed out in the direction of the arrow The position of the hammer and the connecting piece form the chamber: constriction 29 and control head 27 a throttle gap JOj See Fig. 2.

During normal bottom hole operation of the downhole hammer, the compressed air supplied to the connection piece Jt flows through the chamber 28 around the control pin head 27 located in the middle of the chamber, the relatively large annular space formed thereby between the chamber wall and the control head and arrives unthrottled to the channels 22 and in the Air distribution annulus 2J.

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As a result of the pressure built up there, the valve member 17 ^{Λ is} lifted from the valve seat 21 and compressed air flows into the upper cylinder space 60, the percussion piston 7 performs a percussion stroke. ,

Before the end of the base cover, the valve element 17 is reversed and compressed air now passes through the annular spaces 18 and the ducts Ik into the supply ducts 19 to the lower cylinder chamber 6u, so that after the supply line to the upper cylinder chamber is shut off, the return stroke of the percussion piston begins for another change of direction. ·

In the event that a relative displacement occurs in the axial direction between the hammer and drill rod, z. B. as a result of withdrawal of the rods or piercing the drill head of a rock cavity, connecting piece 3 and move Control pin 26 of the Drtiekluftsteuerung 5 relative to each other with the consequent effect that the chamber constriction 29, through which there has been free flow up to that point, is passed through the head 27 of the control pin 26 is filled so far that only one throttle gap 30 remains; see Pig. 2.

The compressed air volume, which has now been reduced by the throttle effect, continues to flow via the controller 5 to the lower and upper cylinder space 6o / 6u and causes the percussion piston to perform a prancing movement within the cylinder β, without hitting the face of the intermediate guide 12.

Only when the throttling effect is canceled again by a displacement movement of the connection piece -J> towards the control pin 26 (pushed-in position) does the Bohrloohharnmcr continue to work in normal operation.

According to FIG. J5 and H which also iet the Druckluftdurchlaß permitting and formed as a hollow carrier shaft connecting piece 3 with oblique, radially directed through passages 34 provided and the free end of the connecting Stuckes 4 (outer Eineöhn'iirung 33>) on the outside by a small amount in the through -

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-bernessen knife smaller than the inner wall of the connecting piece surrounding the. Closure cap 2. This cap v / i ede ruin- has an inner wall J> 1 which is enlarged in the shape of a truncated cone at the end directly facing the control unit 5.

4 shows the normal position of the connecting piece 2 to the cap 2 and to the control 5 · In this position the compressed air flows over the relatively wide available Annular space 52 to the channels 22 of the compressed air control 5

In the event that an axial Raltiv displacement between If the hammer and drill pipe enter, connector 3 will move and cap 2 relative to each other with the consequence: that the up to then freely flowed through annular space 32 - now to one Throttle gap 35 receded - flow is through · (Fig. 4) and the compressed air volume for control, which has been reduced by throttling 5 flows and brings about the same prancing piston movement, which is brought about with the control measure of the control pin in the cavity of the connector.

BATH

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Claims (1)

FHA Pokorny JfJ ^ October 1969 Frankfurt mechanical engineering A3 * ^w 5T- ¹ IA 2 - Thu / Ski Frankfurt (Main) -West 13
Solrnsstrasse 2/26 "'■■"' Claims 1. Percussion hammer, consisting of cylinder, percussion piston, Drill head and hollow connection piece for the drilling * linkage, as well as with a compressed air control, marked by one depending on the axial relative movement between Percussion hammer (1,2,8,10) and connection piece (3) throttle gap created in the lifted end position (30) at d "- *", aluminum outlet end of the connection piece (.;. «I« r by an internal constriction (29) a chamber (28) through which compressed air flows in the connection piece (J) and a control head (27) one in the Chamber (28) protruding arranged control pin (26) of the compressed air control (5) formed v.'ird. 2, percussion hammer according to claim 1, 'characterized in that that the chamber (28) and the control head (27) are so designed and are arranged that the inserted in the End position of the connection piece (35) in the middle of the chamber located control head a ring cam forms. J>. Percussion hammer, consisting of cylinder, percussion piston, drill head and hollow connection piece for the drill rod, as well as with a compressed air control, characterized by 1 098ΐ8 / 1227 bath • · PMA 2 - Thu / Ski -S- 1950508 10/2/69 one depending on the axial relative movement between Percussion hammer (1,2,8,10) and connecting piece (3) inöer extended end position created throttle gap (35) at the end of the connection set on the compressed air outlet side (J5), which by an outer constriction (53) of the free end of the connecting piece (»and the Inner wall of the connecting piece leading hammer body (2) is formed. 4. Sehlagbohrhamnier according to claim 3 »characterized in that that the inner wall of the body (2) in the direction of the control (5) behind the throttle gap (35) is conical in shape is designed expanded and in the inserted end position of the connecting piece (3) together forms an enlarged annular chamber (32) with the surface (33). BATH ORIGINAL 109816/1227